The present invention relates to a technology which uses electro-optical elements.
Electro-optical elements, such as OLED (Organic Light Emitting Diode) elements or the like, emit light themselves when a current flows therein. The electro-optical elements are current-controlled light-emitting elements that are turned off when the supply of the current stops. Accordingly, in order to ensure sufficient luminance so as to maintain the light emission of such an electro-optical element, a structure for continuously supplying the current to an OLED element needs to be provided. In view of this situation, in the related art, a configuration in which a capacitor serving as a current supply source to the OLED element is provided for each pixel has been suggested. For example, in Japanese Unexamined Patent Application Publication No. 8-54836 (FIG. 11), a configuration has been disclosed in which an electric charge according to the gray-scale level of each electro-optical element is accumulated in a capacitor in a horizontal scanning period and, with the electric charge accumulated in the capacitor, a current is supplied to the electro-optical element after the horizontal scanning period lapses. On the other hand, in such a configuration, in order to cause the electro-optical element to continuously emit light over a predetermined length of time, sufficient electrostatic capacitance of the capacitor needs to be ensured. Then, in Japanese Unexamined Patent Application Publication No. 2002-366058, a configuration has been disclosed in which a plurality of electrodes and a plurality of dielectrics are laminated.
However, in the technology disclosed in Japanese Unexamined Patent Application Publication No. 2002-366058, in order to laminate the electrodes and the dielectrics of the capacitor, a photolithography process needs to be repeatedly performed several times, which results in a problem in that a manufacturing process is complicated, manufacturing costs are increased, and yield is degraded. In particular, when the pixel is reduced in size in order to realize a high-definition image, the capacitor must be reduced in size. Accordingly, the manufacturing costs or the yield cannot be maintained at a realistic level.